276 Peach-Growing 



Methods of control of root^rot. 



Usually the disease has progressed so far when discovered 

 that little or nothing of material value can be done to save 

 an affected tree. A method reported from Oregon con- 

 sists in removing most of the soil early in the season from 

 the area occupied by diseased roots, cutting off those that 

 are affected and cleaning away diseased bark at the crown. 

 After disinfecting the wounds, the parts are left exposed 

 to the air for a considerable length of time. This "aeration 

 method," as it is called, is said to offer some promise. 



When a single tree here and there in an orchard is affected, 

 the "trenching method" has been suggested. This consists 

 in digging a trench a foot wide and two feet or more deep 

 and at a sufficient radius from the tree to leave all the 

 diseased roots on the side of the trench next the tree. The 

 soil from the trench should be thrown towards the tree. 

 This results merely in isolating the diseased tree from its 

 neighbors, which are presupposed to be uninfected when this 

 method is used, the disease spreading gradually through the 

 * soil if not restricted. 



The various diseases causing root-rot may live for a long 

 time as saprophytes on dead parts of roots or other pieces 

 of wood that may be in the soil. Therefore, after the re- 

 moval of a diseased tree, the place should not be filled by 

 replanting another. 



Gummosis 



Gummosis is a rather general term applied to a group of 

 troubles the evidence of which is the exudation of gum 

 from points on the trunk, branches, or twigs. It commonly 

 occurs in the spring, the gum forming in globules which 

 vary in size. At first they are soft, then amber-colored, 



